Biodegradable chewing gum and method of manufacturing such chewing gum

ABSTRACT

The invention relates to a chewing gum comprising gum base, sweetener and flavor, wherein at least a part of said gum base comprises at least one biodegradable polymer, where the tan(delta) is at least 0.6 within the linear viscoelastic region (LVR) of the chewing gum.  
     According to the invention, it has been recognized that the texture may be referred to measurable rheological properties of the final chewing gum.  
     Furthermore, it has been realized that biodegradable polymers may be adjusted towards desired rheological properties by means of so-called plasticizers, even if the chewing gum is made on the basis of biodegradable polymers, which as from the beginning, does not meet desired rheological properties.

FIELD OF THE INVENTION

[0001] The present invention relates generally to the field of chewinggum manufacturing and in particular to a method for preparing a chewinggum which comprises an at least partially degradable gum base. Themethod results in a chewing gum having an acceptable texture profile.

BACKGROUND OF THE INVENTION

[0002] It is generally recognized that chewing gum that is dropped inindoor or outdoor environments gives rise to considerable nuisances andinconveniences due to the fact that the dropped gum sticks firmly toe.g. street and pavement surfaces and to shoes and clothes of peoplebeing present or moving in the environments. Adding substantially tosuch nuisances and inconveniences is the fact that currently availablechewing gum products are based on the use of elastomeric and resinouspolymers of natural or synthetic origin that are substantiallynon-degradable in the environment. Accordingly, several attempts havebeen made in order to develop degradable or biodegradable chewing gum.

[0003] Degradable chewing gum bases have been disclosed in U.S. Pat. No.6,153,231 which comprises poly(lactic acid) co-polymers selected frompoly(lactid acid-dimer-fatty acid-oxazoline) copolymers and poly(lacticacid-diol-urethane) copolymers.

[0004] U.S. Pat. No. 5,672,367 discloses degradable chewing gum madefrom certain synthetic polymers with chemical unstable bonds in theirpolymer chains which can be broken under the influence of light orhydrolytically into water-soluble and non-toxic components. The claimeddegradable chewing gum comprises at least one degradable polyesterpolymer obtained by the polymerisation of cyclic esters, e.g. based onlactides, glycolides, trimethylene carbonate and ε-caprolactone.

[0005] However, such gum bases typically do not posses the appropriaterheological properties in order to make a chewing gum having acceptabletexture properties. Accordingly, it can be difficult to provide anappropriate degradable gum base or gum base ingredient in order to forma chewing gum having good texture properties.

[0006] Several attempts to obtain a biodegradable chewing gum, which maycomplement or even replace traditional non-degradable chewing gum, havebeen made within the prior art.

[0007] A process for manufacturing of such polymers has for example beendisclosed in U.S. Pat. No. 5,672,367. According to U.S. Pat. No.5,672,367, the obtained polymer is prepared by melting the gum baseformed by at least one polyester polymer.

[0008] However, one problem, when for example applying biodegradablesubstitutes in gum base and in chewing gums, is that the chewing gumtexture “feels wrong” compared to conventional chewing gums, which,inevitably forms the reference to consumers of such products. Extensiveexperimentation has been performed in order to overcome this problem.

[0009] Basically, the biodegradable polymers available for themanufacturing of chewing gum according to the prior art tend to behaveso very different from traditional gum base components. It has thereforebeen extremely difficult to emulate the properties of traditionalchewing gums.

[0010] Therefore, great effort has been put into the process ofproviding suitable biodegradable chewing gum components, such aspolyesters obtained by polymerization of cyclic esters.

[0011] It is an object of the invention to provide chewing gum, whichmay inherit properties comparable to conventional non-biodegradablechewing gum when applying the above mentioned biodegradable polymers.

SUMMARY OF THE INVENTION

[0012] The invention relates to a chewing gum comprising gum base,sweetener and flavor, wherein at least a part of said gum base comprisesat least one biodegradable polymer, where

[0013] the tan(delta) is at least 0.6 within the linear viscoelasticregion (LVR) of the chewing gum and where

[0014] the tan(delta) is defined as tan δ(ω)=(loss modulus G″/storagemodulus G′).

[0015] According to the invention, chewing gum may be obtained by meansof several different types of biodegradable polymers as described in WO01/47368, WO 00/19837, WO 98/17123, U.S. Pat. No. 6,153,231, WO00/35297, WO 98/17124, U.S. Pat. No. 6,017,566, hereby incorporated byreference.

[0016] According to the invention, it has been recognized that thetexture may be referred to measurable rheological properties of thefinal chewing gum.

[0017] Furthermore, it has been realized that biodegradable polymers maybe adjusted towards desired rheological properties by means of so-calledplasticizers, even if the chewing gum is made on the basis ofbiodegradable polymers, which as from the beginning do not meet desiredrheological properties.

[0018] According to the invention, plasticizers in a broad sense e.g.comprise aroma and flavoring agents, softeners, liquid sweeteners,emulsifiers, solubilizers, waxes and oils.

[0019] Specific examples may e.g. include triacetine, lecithin.

[0020] Further, it has been determined, that the plasticizers may evencompensate properties of biodegradable polymers, which, as from thestart of the process, seem to be inferior compared to conventionalnon-biodegradable chewing gum components.

[0021] According to one embodiment of the invention, properties ofchewing gum, which were deemed less acceptable with respect to e.g.texture based on traditional non-degradable gum polymers, were partlycompensated or even completely compensated by means of rheologicaltuning by means of plasticizers.

[0022] According to a further embodiment of the invention, chewing gumpartly comprising degradable polymers, may also be tuned into chewinggum having commercial attractive properties.

[0023] The tan(delta) is at least 0.6 within the viscoelastic region(LVR) when measured at a temperature of the approximatein-use-temperature and measured by standard oscillation test setups at afrequency of the approximate in-use frequency, i.e. in a frequency bandclose to 1 Hz.

[0024] In-use temperature is typically around 34 C°, i.e. close to mouthtemperature.

[0025] According to the invention, a partly or completely acceptablebiodegradable chewing gum has been provided on the basis ofbiodegradable polymers.

[0026] According to the invention, chewing gum having acceptable textureprofiles has been prepared on the basis of biodegradable gum bases inspite of the fact, that the basic biodegradable polymers, compared toconventional gum base or gum base ingredients, seem to be inferior.

[0027] Moreover, it has been suggested that this tan(delta) may even belower than tan(delta) of conventional non-biodegradable chewing gums.

[0028] It should be noted that the tan(delta) should preferably bemeasured at near body-temperature in order to reflect the relevantproperties of the chewing gum.

[0029] Moreover, according to an embodiment of the invention, a chewinggum comprising a very significant amount of biodegradable polymers hasbeen obtained having properties allowing commercial exploitation withrespect to rheological parameters.

[0030] When the tan(delta) increases outside the linear viscoelasticregion (LVR), a further advantageous embodiment of the invention hasbeen obtained.

[0031] Typically, materials and chewing gums as such are evaluated andtherefore designed in order to obtain certain rheological propertieswithin the so-called linear viscoelastic region, also referred to as LVRwithin the art.

[0032] According to the invention, it has moreover been realized thatnonlinear properties are extremely important when evaluating andestablishing a chewing gum end product. The nonlinear properties maythus reflect the textural behavior of the chewing gum, i.e. duringtypical mechanical induced conditions rendering the chewing gumnonlinear viscoelastic properties. This feature will be describedthoroughly below.

[0033] When the tan(delta) is tuned by means of at least oneplasticizer, a further advantageous embodiment of the invention has beenobtained.

[0034] According to the invention, relatively simple measures have beenprovided for the purpose of optimizing chewing gum comprisingbiodegradable or partly biodegradable polymers of chewing gums.

[0035] When the tan(delta) is increased by adding plasticizer to thechewing gum, a further advantageous embodiment of the invention has beenobtained.

[0036] According to the invention, plasticizer may typically be addedduring mixing, i.e. when the final chewing gum is prepared on the basisof gum base or the chewing gum components as such.

[0037] When the tan(delta) is increased outside the linear viscoelasticregion (LVR) by adding plasticizer to the chewing gum, a furtheradvantageous embodiment of the invention has been obtained.

[0038] When, the slope of the tan(delta) outside the linear viscoelasticregion (LVR) relative to oscillation torque is increased by addingfurther plasticizer to the chewing gum, a further advantageousembodiment of the invention has been obtained.

[0039] According to an embodiment of the invention, a decreasedtan(delta) may of course be obtained by reducing the amount ofplasticizers.

[0040] When the tan(delta) increases to at least 1.0 in the nonlinearviscoelastic region (non-LVR), a further advantageous embodiment of theinvention has been obtained.

[0041] According to a preferred embodiment of the invention, thetan(delta) should preferably increase to at least 1.0 (one) whenentering into the nonlinear region. Typically, the upper value of thetan(delta) is obtained at delamination, i.e. when a nonlinear measuringis no longer applicable by available dynamical measurement setups.

[0042] Preferably, the tan(delta) increases to at least 1.1 in thenonlinear viscoelastic region (non-LVR).

[0043] More preferably, the tan(delta) increases to at least 1.2 in thenonlinear viscoelastic region (non-LVR).

[0044] More preferably, the tan(delta) increases to at least 1.5 in thenonlinear viscoelastic region (non-LVR).

[0045] Typically, the tan(delta) should increase to the above mentionedvalues within an oscillation torque of 10000-25000 microN·m.

[0046] When the tan(delta) increases to at least 1.0 in the nonlinearviscoelastic region (non-LVR), when an oscillation torque of 10000microN·m has been reached, a further advantageous embodiment of theinvention has been obtained.

[0047] Typically, oscillation torque may be measured by means ofso-called SAOS-tests.

[0048] When the tan(delta) increases to at least 1.3 in the nonlinearviscoelastic region (non-LVR) when an oscillation torque of 10000microN·m has been reached, when measured on chewed chewing gum, afurther advantageous embodiment of the invention has been obtained.

[0049] When the tan(delta) increases to at least 1.3 in the nonlinearviscoelastic region (non-LVR), when an oscillation torque of 11000microN·m has been reached, and when measured on chewed chewing gum, afurther advantageous embodiment of the invention has been obtained.

[0050] When the tan(delta) increases to at least 1 within one decadefrom the transition between the linear viscoelastic region into thenonlinear viscoelastic region, when the tan(delta) measured as afunction of oscillation torque, a further advantageous embodiment of theinvention has been obtained.

[0051] When the tan(delta) is tuned to have a maximum of approximately2.0 or preferably 1.7 when the oscillation torque is less than 13000microN·m, a further advantageous embodiment of the invention has beenobtained.

[0052] When the tan(delta) is measured on pre-chewed chewing gum, afurther advantageous embodiment of the invention has been obtained.

[0053] When the tan(delta) is measured at mouth temperature, a furtheradvantageous embodiment of the invention has been obtained.

[0054] Moreover, when the tan(delta) is measured within a range ofapproximately 30 C° to 45 C°, a further advantageous embodiment of theinvention has been obtained.

[0055] It should be noted, that these measuring temperatures may benecessary due to the fact that the available measurement methods are notcapable of dealing with high stiffness.

[0056] When the tan(delta) is measured at an oscillation frequencycorresponding to typical chewing frequency, a further advantageousembodiment of the invention has been obtained.

[0057] When the tan(delta) is measured at an oscillation frequency of1.0 Hz, a further advantageous embodiment of the invention has beenobtained.

[0058] When the tan(delta) is measured at an oscillation frequencywithin a range of 0.5 to 2 Hz, a further advantageous embodiment of theinvention has been obtained.

[0059] A further advantageous embodiment has been obtained when theplasticizers comprise emulsifiers, preferably in an amount of 0 to 5%w/w.

[0060] A further advantageous embodiment has been obtained when theplasticizers comprise fat, preferably in an amount of 0 to 15% w/w.

[0061] A further advantageous embodiment has been obtained when theplasticizers comprise wax, preferably in an amount of 0 to 15% w/w.

[0062] A further advantageous embodiment has been obtained whenplasticizers comprise solubilizers, preferably in amount of 0 to 5% w/w.

[0063] A further advantageous embodiment has been obtained when theplasticizers comprise flavor, preferably liquid flavor, preferably in anamount of 0 to 30% w/w.

[0064] A further advantageous embodiment has been obtained whenplasticizers comprise liquid sweeteners, preferably in an amount of 0 to30% w/w.

[0065] According to the invention, the chewing gum may comprise anamount of biodegradable polymers of 1 to 99% w/w.

[0066] According to a further advantageous embodiment of the invention,the chewing gum partly comprises non-biodegradable polymers.

[0067] The linear viscoelastic region (LVR) has a maximum oscillationtorque within a range of 300 microN·m to 10000 microN·m, preferablywithin a range of 400 microN·m to 3000 microN·m. and most preferablywithin a range of 500 microN·m to 2000 microN·m.

[0068] Moreover, the tan(delta) critical is greater than 0.7, preferablygreater than 0.8 preferably greater than 1.0 where the tan(delta)(crit)is the tan(delta) value corresponding to delta(crit) in a tan(delta) vs.oscillation torque measurement and where delta(crit) represents thecritical oscillation torque determined in a G′ vs. oscillation torquemeasurement, which describes the oscillation torque at the point wherethe material begins to deform, i.e. the point where the oscillationtorque invokes a transition from the LVR to the non-LVR.

[0069] Preferably the tan(delta) critical is less than 1.0, preferablygreater than 0.9 preferably greater than 0.8.

[0070] The biodegradable polymers may e.g. comprisepoly(ester-carbonate) comprising monomers selected from the groupconsisting of lactide, glycolide, ε-caprolactone, δ-valerolactone,β-propiolactone, dioxanone (ester-ether), tri-methylene carbonate,ethylene carbonate, propylene carbonate, 5,5 di-methyl-1,3-dioxane-2-oneand 5-methyl-1,3-dioxane-2-one.

[0071] The polyester may comprise a homopolymer, co-polymer or ater-polymer.

[0072] The molecular weight of the degradable polymer is in the range of500-10.000 g/mol, within the range of 10000-100.000 g/mol or within therange of 100000-1000.000 g/mol.

[0073] Moreover, the invention relates to a method of manufacturing abiodegradable chewing gum comprising the steps of providing at least onebiodegradable polymer and adding plasticizer to the said at least onebiodegradable polymer in an amount suitable for tuning the balancebetween the loss modulus and the storage modulus.

THE DRAWINGS

[0074] The invention is explained in details with reference to thedrawings where

[0075]FIGS. 1a-1 c illustrate rheological properties of gum baseformulations,

[0076]FIGS. 2a-2 c illustrate rheological properties of unchewed chewinggums,

[0077]FIGS. 3a-3 c illustrate rheological properties of chewed chewinggums

[0078]FIGS. 4a-4 c illustrate rheological properties of chewed chewinggums tuned according to the invention.

[0079]FIG. 5 illustrates a test setup applied for verification andtuning according to one embodiment of the invention.

DETAILED DESCRIPTION

[0080] Table 1 refers to the involved gum bases and chewing gums.

[0081] Table 2 illustrates the basic formulation of 1021 chewing gumbase.

[0082] Table 3 illustrates the basic formulation of 1023 chewing gumbase.

[0083] Table 4 illustrates the basic formulation of 1025 chewing gumbase.

[0084] Table 5 illustrates the basic formulation of 1020 chewing gumbase.

[0085] Table 6 illustrates the basic formulation of CG SUB 4 chewinggum.

[0086] Table 7 illustrates the basic formulation of 1525-1530 and1556-1561 chewing gum.

[0087]FIG. 1a to FIG. 1c illustrate the rheological properties of gumbases tested and applied according to the invention.

[0088] Involved gum bases and chewing gums are listed in table 1.

[0089] Generally, the below measurements have been performed asillustrated and described with reference to FIG. 5. Moreover, theexplaining associated to FIG. 5 introduces the main rheologicaldefinitions referred to according to the invention.

[0090] The term gum base may refer broadly to a composition ofelastomers, resins, fillers and softeners or e.g. a polymer itself.

[0091] According to conventional chewing gum manufacturing the gum basemay be mixed with flavor, sweeteners, etc. into a final chewing gum and,if desired, subsequently be coated.

[0092]FIG. 1a to FIG. 1c illustrate measuring at a temperature of 70° C.

[0093]FIG. 1a to FIG. 1c illustrate a number of gum bases. Details aboutthe illustrated gum bases are described in table 1.

[0094]FIG. 1a illustrates the tan(delta) of a number of different gumbases as a function of oscillation torque (microN·m).

[0095] It is observed, that the tan(delta) of the GB SUB 3 and GB SUB 4is significantly higher than the other group of gum bases.

[0096] It is noted, that the lower group of gum bases comprises bothbiodegradable, partly degradable and standard non-degradable gum bases.

[0097] No significant differences between the lower group of gum basesare observed.

[0098] An immediate thought is that the 100% biodegradable gum bases GBSUB 3 and GB SUB 4 are more or less useless for the purpose of obtainingan acceptable chewing gum texture.

[0099]FIG. 1b illustrates the storage modulus G′ (Pa) as a function ofoscillation torque (microN·m) of the gum bases of FIG. 1a.

[0100]FIG. 1c illustrates the loss modulus G″ (Pa) as a function ofoscillation torque (microN·m) of the gum bases of FIG. 1a.

[0101]FIG. 2a to FIG. 2c illustrate measurement at a temperature of 45°C.

[0102]FIG. 2a illustrates the tan(delta) of a number of chewing gumsbased upon a selection of the gum base components as illustrated in FIG.1a to FIG. 1c.

[0103]FIG. 2a to FIG. 2c refer to un-chewed chewing gum. Again, thetan(delta) is as measured as a function of oscillation torque(microN·m).

[0104] It is noted, that e.g. 1552 and 1553 show an increased tan(delta)even within the LVR (determined by G′).

[0105] Moreover it is noted, that chewing gums prepared on the basis ofbiodegradable polymers apparently are comparable to conventionalnon-biodegradable chewing gums.

[0106] It is noted, that chewing gums should preferably exhibit an LVRof at least 300 microN·m in order to facilitate subsequent processinginto the final chewing gum shape, e.g. by means of rolling and scoring.Moreover, subsequent processing includes coating, packaging anddistribution. An LVR of less than the suggested limit would result inthe obtained chewing gum having a somewhat viscous nature which isunable to maintain the desired dimensions.

[0107] And immediate impression is that all the evaluated chewing gumsexhibit an acceptable minimum LVR.

[0108] Moreover, it should be noted, that the LVR should exhibit amaximum of not more than approximately 10000 microN·m in order tofacilitate subsequent processing. An LVR which is greater than thesuggested limit would result in a dry, crumpling substance.

[0109] It is noted, that both 1554 0% and 1554 2.5% seem to be lesssuitable for chewing gum.

[0110]FIG. 2b illustrates the storage modulus G′ (Pa) as a function ofoscillation torque (microN·m) of the chewing gums of FIG. 2a.

[0111]FIG. 2c illustrates the loss modulus G″ (Pa) as a function ofoscillation torque (microN·m) of the chewing gums of FIG. 2a.

[0112]FIG. 3a to FIG. 3c illustrate measuring at a temperature of 37° C.

[0113]FIG. 3a to FIG. 3c refer to chewed chewing gum.

[0114]FIG. 3a illustrates the tan(delta) of a number of chewing gumsbased upon a selection of the gum bases as illustrated in FIG. 1a toFIG. 1c.

[0115] Again, the tan(delta) is measured as a function of oscillationtorque (microN·m).

[0116] The illustrated properties will now be commented with referenceto the texture describing parameters as stated in table 1.

[0117] Initially it is noted, that the chewing gums 1526, 1528 and 1530are acceptable or almost acceptable (1526 is a standard chewing gum and1528 and 1530 partly comprise biodegradable polymers). It is moreovernoted, that all the chewing gums never reaching a tan(delta) value of atleast approximately 1.0 within the measurable range of oscillationtorque, have been deemed unacceptable by texture evaluation.

[0118] It should be noted, that the chewing gum CG SUB 4 based on thegum base GB SUB 4 is not reproduced on the illustrated FIGS. 3a-c.However, the chewing gum was tested and deemed acceptable by a textureevaluation panel.

[0119] It is noted, that the slope of the tan(delta) of acceptablechewing gum is within a range of 0.2 and 0.9 when measured within thenon-LVR.

[0120] Specifically it is noted, that a slope of the tan(delta) of thechewing gums 1526, 1528 and 1530 are 0.34, 0.26 and 0.17 respectively.1525 1554 1530 1528 1526 1553 1552 Slope 0.05 0.10 0.17 0.26 0.34 0.952.28 tan (δ)

[0121] The slope of the tan(delta) has been determined as the tangent tothe curves within the non-LVR region, when measured by the last (herefour) measuring points prior to measuring halt (e.g. at delamination orslip).

[0122] The slope of the the tan(delta) indicates that the non-LVR regionis important for chewing gum evaluation in the sense that a small sloperesults in an overall rigid and stiff texture which is less suitable forchewing gum and a high slope results in a soft or buttery texture, alsoless suitable for chewing gum.

[0123]FIG. 3b illustrates the storage modulus G′ (Pa) as a function ofoscillation torque (microN·m) of the chewing gums of FIG. 3a.

[0124]FIG. 3c illustrates the loss modulus G″ (Pa) as a function ofoscillation torque (microN·m) of the chewing gums of FIG. 3a.

[0125]FIG. 4a to FIG. 4c illustrate measuring at a temperature of 37° C.

[0126]FIG. 4a to FIG. 4c illustrate the tan(delta), G′(Pa) (storagemodulus) and G″ (Pa)(loss modulus) of chewing gum comprisingbiodegradable polymers as a function of oscillation torque (microN·m).

[0127]FIG. 4a to FIG. 4c refer to a chewed chewing gum.

[0128] The illustrated chewing gums which are mutually in compositiondiffer by the amount and type of plasticizer. For details about theillustrated chewing gums and the applied amount tuning plasticizers, seetable 1.

[0129] Explanatory notes to the texture evaluation, as described inbroad terms in table 1, will be discussed below.

[0130] Basically, a texture evaluation of the chewing gums revealed thatan improved texture was obtained by an increased tan(delta) within themeasurable area (i.e. the area in which the available measuringequipment are capable of dealing with) of the nonlinear viscoelasticregion.

[0131] A short summary of comparisons between the chewing gum samples isstated below.

[0132] The texture (subjective) evaluation rated the chewing gums,starting from the best chewing gum: 1557, 1561, 1560, 1559, 1558 and1556.

[0133] A remarkable result is therefore that a subjective evaluation maydirectly be correlated to objective physical properties and that theobjective physical properties of chewing gums comprising biodegradablepolymers may be tuned by means of variation of the plasticizers.

[0134] According to the invention, it has therefore been realized thatbiodegradable or partly biodegradable chewing gum may be adjusted bymeans of plasticizers.

[0135]FIG. 5 illustrates a measuring setup for measuring of differentrelevant rheological parameters applied according to the invention toobtain the desired end product, i.e. the chewing gum.

[0136] According to the invention, rheology may be applied for the studyof the viscoelastic properties of gum base raw materials, gum bases andchewing gums. By applying for example small amplitude oscillating stressor strain (SAOS) to the sample it is possible to obtain informationconcerning the microscopic interactions in the sample. This informationmay be used for the prediction of properties related to texture andprocessing behavior of gum base raw materials, gum bases and chewinggums.

[0137] Deformation is measured both in the non-destructive region, i.e.the so-called linear viscoelastic region (LVR) as well as at higherstresses outside the LVR giving the shear stress/shear raterelationships.

[0138] The results of the viscoelastic measurements may be expressed asG′ (storage modulus), G″ (loss modulus) and tan (δ)=G″/G′.

[0139] G′ represents elastic storage of energy and is a measure of howwell structured the sample is. If the storage modulus is predominantlyhigh the sample is highly structured and vices versa. If the structureis being destroyed the G′ will decrease and the critical stress (orstrain) amplitude can be determined giving information about resistanceto deformation.

[0140] G″ represents the viscous dissipation or loss of energy. If theloss modulus is high, the sample is predominantly viscous.

[0141] Tan (δ) represents phase difference between the input and theoutput. δ will increase with increasing viscous behavior and decreasewith increasing elastic behavior.

[0142] δ(crit) represents the critical oscillation torque (or stressamplitude) determined in a G′ vs. oscillation torque measurement, whichdescribes the oscillation torque at the point where the material beginsto deform, i.e. the point where the oscillation torque invokes atransition from the LVR to the non-LVR.

[0143] Tan (δ)(crit) is the tan (δ) value corresponding to δ(crit) in atan (δ) vs. oscillation torque measurement.

[0144]FIG. 5 illustrates schematically an applicable dynamic measuringmethod, a so-called controlled-stress-technique, which may be appliedfor the evaluation of the viscoelastic properties of gum base rawmaterials, gum bases and chewing gums.

[0145] It should be mentioned, that other dynamic measuring methods maybe applied for the measuring of the desired material properties, e.g.wave propagation or steady flow methods.

[0146] An applicable rheometer is AR 1000 supplied by TA Instruments.This rheometer has been applied for measuring in FIG. 1a-to FIG. 4c.

[0147] All the measurements have been made by means of a parallel plate,hatched plates, and a diameter of 2 (two) cm.

[0148] The illustrated measuring setup comprises a stationary base plate51 arranged relative to a measuring head 52 arranged at the end of adrive rod 53.

[0149] The rod may rotate (and oscillate) around its axis with anangular velocity ω (rad s⁻¹) which is a result of a motor controlledinduced stress.

[0150] When performing the above mentioned measurements parallel plateshave been applied (in stead of for example a cone) due to the fact thatparallel plates allow samples containing particles to be effectivelymeasured.

[0151] The resulting angular movement of the disc, and thereby theresulting strain, may be measured by means of optical encoders (notshown) arranged for detection of the resulting strain.

[0152] It should be noted, that the above mentioned parameters G′storage modulus and G″ loss modulus may be referred to by other nameswithin the art, e.g. G′ as elastic modulus and G″ as viscous modulus.Still, the same definitions apply.

[0153] The storage modulus G′ is a measure of a material's ability tostore recoverable energy. This energy storage can be the result of theability of a complex polymer, structural network, or a combination ofthese to recover stored energies after a deformation.

[0154] The linear viscoelastic region is a region where there is alinear relationship between stress and strain.

[0155] The loss modulus G″ is a measure of the unrecoverable energy,which has been lost due to viscous flow.

[0156] The tan(delta) is defined as (loss modulus G″/storage modulusG′). In other words, the tan(delta) may express the relation between thematerials ability to flow and perform reversible elastic regeneration ofthe shape and configuration of the material upon external mechanicaldeformation, i.e. the ability to recover.

[0157] According to the invention, the measurements have been performedunder conditions as close as possible to application conditions,whenever possible.

[0158] Application conditions may e.g. refer to frequency, temperatureand stress.

[0159] The relevant frequency has typically been adjusted at one Hz dueto the fact that normal chewing comprises a dominant chew frequencycomponent of approximately 1 (one) Hz.

[0160] It should of course be noted, that higher and lower frequencycomponents may be relevant in order to evaluate and design a chewinggum. However, the most relevant frequencies relevant for evaluation willbe the frequencies in a band around the above stated one Hz. TABLE 1Chewing gum and gum base references Corresponding Texture Gum base No.Chewing gum No. Characteristic evaluation GB Sub 3 CG Sub 3 GB: 100%elastomer sub 3 Rigid, hard, plastic. Not acceptable texture GB Sub 4 CGSub 4 GB: 100% elastomer sub 4 Rigid, hard, plastic. Not acceptabletexture 1020 1525 GB: 7% elastomer Crumbling, stiff, substituted withelastomer plastic sub. 2, 43% resins and Not acceptable PVAc substitutedwith texture PVAc sub 1021 1526 Conventional GB Spongy, elastic, softAcceptable pleasant texture 1023 1528 GB: 20% PVAc Spongy, elastic,substituted with PVAc tough sub Acceptable texture 1025 1530 GB: 40%Resins + PVAc Plastic, soft, tough substituted with PVAc Almostacceptable sub texture GB2 1552-5%   CG: 5% Lemon flavor Buttery, soft,Conventional GB viscous Not acceptable texture 1020 1553-5%   CG: 5%Lemon flavor Dry, buttery, GB: 7% elastomer viscous substituted withelastomer Not acceptable sub. 2, 43% resins and texture PVAc substitutedwith PVAc sub 1020 1554-0%   CG: 0% Lemon flavor Hard, crumbling, GB: 7%elastomer disintergrates substituted with elastomer Not acceptable sub.2, 43% resins and texture PVAc substituted with PVAc sub 1020 1554-2.5%2.5% Lemon flavor Hard, crumbling, GB: 7% elastomer rigid substitutedwith elastomer Not acceptable sub. 2, 43% resins and texture PVAcsubstituted with PVAc sub 1025 1556 GB: 40% Resins + PVAc Plastic, soft,tough substituted with PVAc Almost acceptable sub. texture 1023 1557 GB:20% PVAc Spongy, elastic, substituted with PVAc tough sub Acceptabletexture 1025 1558 CB: 3% lycasin less than Plastic, soft, tough 1556Almost acceptable texture 1025 1559 CG: 3% lycasin more Plastic, soft,tough than 1556 Almost acceptable texture 1025 1560 CG: 0.1% lecithinmore Spongy, plastic, than 1556 soft Acceptable texture 1025 1561 CG:0.2% lecithin more Spongy, plastic, than 1556 soft Acceptable textureConventional Conventional CG 1 Conventional GB for Spongy, elastic, GB 1sugarfree CG soft Acceptable pleasant texture Conventional ConventionalCG 2 Conventional GB for Spongy, elastic, GB 2 sugarfree CG softAcceptable pleasant texture Conventional Conventional CG 3 ConventionalGB for Spongy, elastic, GB 3 sugarfree CG soft Acceptable pleasanttexture Conventional Conventional CG 4 Conventional bubble gum Veryspongy, GB 4 elastic, tough Acceptable pleasant texture ConventionalConventional CG 5 Conventional GB for Spongy, elastic, GB 5 sugarfree CGsoft Acceptable pleasant texture Conventional Conventional CG 6Conventional GB for Spongy, elastic, GB 6 sugarfree CG soft Acceptablepleasant texture Conventional Conventional CG 7 Conventional GB forSpongy, elastic, GB 7 medical CG soft Acceptable pleasant texture

[0161] The chewing gums 1556-1561 basically refer to the sameformulation. However, when the amount of plasticizer is increased, theamount of sorbitol is decreased correspondingly, thereby maintaining thesame basic chewing gum formulation as described in table 7. Likewise,the amount of sorbitol is increased correspondingly, when the amount ofplasticizer is decreased.

[0162] The below described gum bases of table 2 to table 5 and chewinggums of table 6 and 7 are made according to the following processes byconventional methods.

[0163] Chewing Gum Base

[0164] Chewing gum base is conventionally prepared using e.g. a batchmixer, a sigma blade mixer, using a mixing time of about one to fourhours per batch. Typically, predetermined amounts of elastomers, resinsand fillers are added to a heated sigma blade mixer having a front torear blade speed ratio of about 2:1. After the initial ingredients havemassed homogeneously, a balance of elastomers, resins, filler,softeners/emulsifiers, waxes (when used) and other ingredients are addedsequentially to the batch mixer and blended until a homogeneous mass isattained. The final mass temperature can be between 80 degree C. and 120degree.C. The completed molten mass is emptied from the mixing kettleinto coated or lined pans, extruded or cast into any desirable shape andallowed to cool off and solidify.

[0165] Chewing Gum

[0166] The gum base can either be added in a solid form and thensoftened by means of heating from the jacket of the mixer or fromfrictional heat generated during the mixing process, or it can be addedin the melted form.

[0167] All of the chewing gum components selected for the particulartype of chewing gum to be processed are mixed thoroughly in anyconventional type of kneading or mixing vessel such as e.g. a kettleprovided with mixing means like e.g. horizontally placed Z-shaped arms,which are capable of intimately mixing the selected chewing gumcomponents to produce a homogeneous chewing gum mass. After mixing thechewing gum it is unloaded and formed using conventional steps for thiswhich are known in the art including forming a chewing gum into e.g.pillows, sticks and cores. The final mass temperature when emptied fromthe mixer can be between 40° C. and 70° C.

[0168] Coating

[0169] After curing or solidifying the chewing gum elements are coated.The coating can be a hard coating, a soft coating or a film coating ofany type that is known in the art, or a combination of such coating.TABLE 2 illustrates the basic formulation of 1021 gum base (1526)Ingredient % Elastomer HW 20 Elastomer LW PVA LW 40 Resin hydrogenatedResin polymerized Fat 25 Emulsifier Wax LW Wax HW Talc 15

[0170] TABLE 3 illustrates the basic formulation of 1023 gum base (1528)Ingredient % Elastomer HW 20 Elastomer LW Resin substitute 20 Resinhydrogenated 20 Resin polymerized Fat 25 Emulsifier Wax LW Wax HW Talc15

[0171] TABLE 4 illustrates the basic formulation of 1025 gum base (1530)Ingredient % Elastomer HW 20 Elastomer LW Resin substitute 40 Fat 25Emulsifier Wax LW Wax HW Talc 15

[0172] TABLE 5 illustrates the basic formulation of 1020 gum base (1525)Ingredient % Elastomer substitute  7 Resin substitute 43 Fat 23Emulsifier Wax LW Wax HW Talc 27

[0173] The below tables 6 and 7 refer to chewing gum formulation.

[0174] It should be noted, that 1526 and 1528 (1525-1530, 1556-1561) aremanufactured on the basis of gum base, whereas CG SUB 4 is made on thebasis of the biodegradable polymer GB SUB 4 itself. TABLE 6 Chewing gumformulation CG SUB 4 Ingredient % standardiseret GB SUB 4 40 Sorbitolpowder 40 Lecithin 0.2 Lycasin 6.0 Peppermint oil 1.70 PeppermintMenthol crystals 0.9 Menthol powder Aspertame 0.2 Acesulfame 0.2 Xylitol10.8

[0175] TABLE 7 Chewing gum formulation 1525-1530, 1556-1561 Ingredient %GB 40 Sorbitol powder 45.60 Lycasin 6.00 Peppermint 1.50 Menthol 0.50Aspertame 0.20 Acesulfame 0.20 Xylitol 6.00

[0176] Chewing Gum Base Formulation

[0177] Generally, a chewing gum base formulation comprises one or moreelastomeric compounds which may be of synthetic or natural origin, oneor more resin compounds, fillers, softening compounds and minor amountsof miscellaneous ingredients such as antioxidants, colorants and others.

[0178] As defined herein, the chewing gum center comprises at least onephysical, chemical or biological degradable elastomeric or resinouspolymer. In contrast to currently used types of elastomers and resins,such polymers can be degraded in the environment after mastication ofthe chewing gum. This gives rise to less environmental pollution thanchewing gums based on non-degradable polymers, as the used chewing gumwill eventually disintegrate and/or be removed more readily by physicalor chemical means from the site where it is dumped.

[0179] As applied herein, the expression “degradable polymer” refers toa chewing gum base component or a chewing gum base which, after dumpingthe chewing gum or even during chewing, is capable of undergoing aphysical, chemical and/or biological degradation. Hereby the dumpedchewing gum waste becomes more readily removed from the site of dumpingor is eventually disintegrated to lumps or particles, which are nolonger recognizable as chewing gum remnants. The degradation ordisintegration of such degradable polymers can be effected or induced byphysical factors such as temperature, light, moisture or by chemicalfactors such as hydrolysis caused by a change in pH or by the action ofappropriate enzymes capable of degrading the polymers.

[0180] In the present context, suitable examples of such environmentalor biological degradable chewing gum base polymers include a polymerselected from the group consisting of esters, carbonates, ethers,amides, urethanes, peptides, homopolymers of amino acids such aspolylysine, and proteins including derivatives hereof such as e.g.protein hydrolysates including a zein hydrolysate.

[0181] Preferred polymers include polymers selected from the groupconsisting of degradable homopolymers, copolymers, terpolymers, block-and graftpolymers.

[0182] A preferred compound is a polyester and particularly usefulcompounds of this type including polyester polymers obtained by thepolymerisation of one or more cyclic esters as disclosed in the U.S.Pat. No. 5,672,367 which is incorporated herein by reference. Thepolymers disclosed in this reference are characterized by havingchemical unstable bonds in the polymer chain which can be broken e.g.hydrolytically or by exposure to light.

[0183] An important feature of the degradable polymers as used herein isthat they contain chemical unstable bonds that can be broken in thechewed chewing gum under environmental conditions. In the presentcontext, the term “environmental condition” denotes indoor and outdoorlocations and the temperature, light and humidity conditions prevailingin such environments. It will be appreciated that the rate ofdegradation of the degradable polymer in chewing gum remnants dropped ina given environment will depend on the above physical conditions. Inpreferred embodiments, the degradable polymer is one where, under anygiven environmental conditions except extreme cold temperatureconditions, i.e. at temperatures below 0° C., at least 5% of unstablebonds, preferably at least 10%, more preferably at least 15% includingat least 25% of unstable bonds are broken after one month to 12 monthsunder environmental conditions.

[0184] In presently preferred embodiments, the at least one degradableelastomeric or resinous polymer of the coated chewing gum element is apolyester polymer made from a cyclic ester selected from the group oflactide, glycolide, trimethylene carbonate, δ-valerolactone,β-propiolactone and ε-caprolactone. Such polymers may be homopolymers,co-or terpolymers, including block or graft co-polymers, such as e.g. acopolymer of lactide and ε-caprolactone including such a copolymerwherein the initial molecular weight ratio between the lactide andε-caprolactone is in the range of 99:1 to 80:20 such as in the range of95:5 to 90:10, and a copolymer of ε-caprolactone and δ-valerolactone.

[0185] Generally, chewing gum base formulations include elastomeric andresinous polymers of different molecular weights. Accordingly, thedegradable polymer can be of an average molecular weight (M_(w)) that isin the range of 500 to 10000 g/mol, the range of 10,000 to 100,000 g/molor the range of 100,000 to 1,000,000 g/mol.

[0186] The chewing gum centers as defined above may comprise a gum basepart where all of the elastomeric or resinous components are degradablepolymers. However, it is within the scope of the invention that the gumbase part, in addition to one or more degradable polymers, contains aproportion of non-degradable polymeric elastomers and/or resins whichmay be natural or synthetic polymers. The proportion of suchnon-degradable polymers may be in the range of 1-99% by weight includingthe range of 5 to 90% by weight such as in the range of 10-50% byweight.

[0187] In this context, useful synthetic elastomers include, but are notlimited to, synthetic elastomers listed in Food and Drug Administration,CFR, Title 21, Section 172,615, the Masticatory Substances, Synthetic)such as polyisobutylene with a gel permeation chromatography (GPC)average molecular weight in the range of about 10,000 to about 1,000,000including the range of 50,000 to 80,000, isobutylene-isoprene copolymer(butyl elastomer), styrene-butadiene copolymers e.g. havingstyrene-butadiene ratios of about 1:3 to about 3:1, polyvinyl acetate(PVA) having a GPC average molecular weight in the range of 2,000 toabout 90,000 such as the range of 3,000 to 80,000 where the highermolecular weight polyvinyl acetates are typically used in bubble gumbase, polyisoprene, polyethylene, vinyl acetate-vinyl laurate copolymere.g. having a vinyl laurate content of about 5 to about 50% by weightsuch as 10 to 45% by weight of the copolymer, and combinations hereof.

[0188] It is e.g. common in the industry to combine a syntheticelastomer having a high molecular weight and a low-molecular-weightelastomer in a gum base. Presently, preferred combinations of syntheticelastomers include, but are not limited to, polyisobutylene andstyrene-butadiene, polyisobutylene and polyisoprene, polyisobutylene andisobutylene-isoprene copolymer (butyl rubber) and a combination ofpolyisobutylene, styrene-butadiene copolymer and isobutylene isoprenecopolymer, and all of the above individual synthetic polymers inadmixture with polyvinyl acetate, vinyl acetate-vinyl lauratecopolymers, respectively and mixtures thereof.

[0189] Useful natural non-degradable elastomers include the elastomerslisted in Food and Drug Administration, CFR, Title 21, Section 172,615,as “Masticatory Substances of Natural Vegetable Origin” includingnatural rubber compounds such as smoked or liquid latex and guayule andother natural gums including jelutong, lechi caspi, massaranduba balata,sorva, perillo, rosindinha, mass aranduba chocolate, chicle, nispero,gutta hang kang, and combinations thereof. The preferred syntheticelastomer and natural elastomer concentrations vary depending on whetherthe chewing gum in which the base is used is adhesive or conventional,bubble gum or regular gum, as discussed below. Presently preferrednatural elastomers include jelutong, chicle, massaranduba balata andsorva.

[0190] In accordance with the invention, the chewing gum base componentswhich are useful may include one or more resinous compounds contributingto obtain the desired masticatory properties and acting as plasticizersfor the elastomers of the gum base composition. In the present context,useful elastomer plasticizers include, but are not limited to, naturalrosin esters, often referred to as ester gums including as examplesglycerol esters of partially hydrogenated rosins, glycerol esters ofpolymerised rosins, glycerol esters of partially dimerised rosins,glycerol esters of tally oil rosins, pentaerythritol esters of partiallyhydrogenated rosins, methyl esters of rosins, partially hydrogenatedmethyl esters of rosins, pentaerythritol esters of rosins. Other usefulresinous compounds include synthetic resins such as terpene resinsderived from alpha-pinene, beta-pinene, and/or d-limonene, naturalterpene resins; and any suitable combinations of the foregoing. Thepreferred elastomer plasticizers will also vary depending on thespecific application, and on the type of elastomer(s) being used.

[0191] A chewing gum base formulation may, if desired, include one ormore fillers including e.g. magnesium and calcium carbonate, sodiumsulphate, ground limestone, silicate compounds such as magnesium andaluminium silicate, kaolin and clay, aluminium oxide, silicium oxide,talc, titanium oxide, mono-, di- and tri-calcium phosphates, cellulosepolymers, such as wood, and combinations thereof.

[0192] The fillers may also include natural organic fibers such as fruitvegetable fibers, grain, rice, cellulose and combinations thereof.

[0193] As used herein the term “plasticizer” designates an ingredient,which softens the gum base or chewing gum formulation and encompasseswaxes, fats, oils, emulsifiers, surfactants and solubilisers.

[0194] A gum base formulation may, in accordance with the presentinvention, comprise one or more fats e.g. tallow, hydrogenated tallow,any completely or partially hydrogenated animal fats, completelyhydrogenated and partially hydrogenated vegetable oils or fats, cocoabutter, degreased cocoa butter, glycerol monostearate, glyceroltriacetate, lecithin, mono-, di- and triglycerides, acetylatedmonoglycerides, fatty acids (e.g. stearic, palmitic, oleic and linoleicacids), and/or combinations thereof.

[0195] To soften the gum base further and to provide it with waterbinding properties, which confer a pleasant smooth surface to the gumbase and reduce its adhesive properties, one or more emulsifiers is/areusually added to the composition, typically in an amount of 0 to 18% byweight, preferably 0 to 12% weight of the gum base. Mono- anddiglycerides of edible fatty acids, lactic acid esters and acetic acidesters of mono- and di- and triglycerides of edible fatty acids,acetylated mono and diglycerides, sucrose polyesters or sugar esters ofedible fatty acids including those disclosed in WO 00/25598, which isincorporated herein by reference, Na-, K-, Mg- and Ca-stearates,lecithin, hydroxylated lecithin, glycerol monostearate, glyceroltriacetate, fatty acids (e.g. stearic, palmitic, oleic and linoleicacids), propylgallates and combinations thereof are examples ofconventionally used emulsifiers which can be added to the chewing gumbase. In case of the presence of a biological or pharmaceutical activeingredient as defined below, the formulation may comprise certainspecific emulsifiers and/or solubilisers in order to disperse andrelease the active ingredient.

[0196] Waxes are conventionally used for the adjustment of theconsistency and for softening of the chewing gum base when preparingchewing gum bases. In connection with the present invention anyconventionally used and suitable type of wax may be used, such as forinstance rice bran wax, polyethylene wax, petroleum wax (refinedparaffin and microcrystalline wax), paraffin, bees' wax, carnauba wax,and candelilla wax.

[0197] Furthermore, the gum base formulation may, in accordance with thepresent invention, comprise colorants and whiteners such as FD&C-typedyes and lakes, fruit and vegetable extracts, titanium dioxide andcombinations thereof. Further useful chewing gum base components includeantioxidants, e.g. butylated hydroxytoluene (BHT), butyl hydroxyanisol(BHA), propylgallate and tocopherols, and preservatives.

[0198] The composition of chewing gum base formulations which areadmixed with chewing gum additives as defined below can varysubstantially depending on the particular product to be prepared and onthe desired masticator and other sensory characteristics of the finalproduct. However, typical ranges (weight %) of the above gum basecomponents are: 5 to 100% by weigth elastomeric compounds, 5 to 55% byweight resin, 0 to 50% by weight filler, 5 to 35% by weight plasticizerand 0 to 1% by weight of miscellaneous ingredients such as antioxidants,colorants, etc.

[0199] Chewing Gum Additives

[0200] A chewing gum center formulation comprises, in addition to theabove water-insoluble gum base components, a generally water-solublepart comprising a range of chewing gum additives. In the presentcontext, the term “chewing gum additive” is used to designate anycomponent, which in a conventional chewing gum manufacturing process isadded to the gum base. The major proportion of such conventionally usedadditives is water soluble, but water-insoluble components, such as e.g.water-insoluble flavoring compounds, can also be included.

[0201] In the present context, chewing gum additives include bulksweeteners, high intensity sweeteners, flavoring agents, softeners,emulsifiers, coloring agents, binding agents, acidulants, fillers,antioxidants and other components such as pharmaceutically orbiologically active substances, conferring desired properties to thefinished chewing gum product.

[0202] Suitable bulk sweeteners include both sugar and non-sugarsweetening components. Bulk sweeteners typically constitute from about 5to about 95% by weight of the chewing gum, more typically about 20 toabout 80% by weight such as 30 to 70% or 30 to 60% by weight of the gum.

[0203] Useful sugar sweeteners are saccharide-containing componentscommonly known in the chewing gum art including, but not limited to,sucrose, dextrose, maltose, dextrins, trehalose, D-tagatose, driedinvert sugar, fructose, levulose, galactose, corn syrup solids, and thelike, alone or in combination.

[0204] Sorbitol can be used as a non-sugar sweetener. Other usefulnon-sugar sweeteners include, but are not limited to, other sugaralcohols such as mannitol, xylitol, hydrogenated starch hydrolysates,maltitol, isomalt, erythritol, lactitol and the like, alone or incombination.

[0205] High intensity artificial sweetening agents can also be usedalone or in combination with the above sweeteners. Preferred highintensity sweeteners include, but are not limited to sucralose,aspartame, salts of acesulfame, alitame, saccharin and its salts,cyclamic acid and its salts, glycyrrhizin, dihydrochalcones, thaumatin,monellin, sterioside and the like, alone or in combination. In order toprovide longer lasting sweetness and flavor perception, it may bedesirable to encapsulate or otherwise control the release of at least aportion of the artificial sweeteners. Techniques such as wetgranulation, wax granulation, spray drying, spray chilling, fluid bedcoating, conservation, encapsulation in yeast cells and fiber extrusionmay be used to achieve desired release characteristics. Encapsulation ofsweetening agents can also be provided using another chewing gumcomponent such as a resinous compound.

[0206] Usage level of the artificial sweetener will vary considerablyand will depend on factors such as potency of the sweetener, rate ofrelease, desired sweetness of the product, level and type of flavor usedand cost considerations. Thus, the active level of artificial sweetenermay vary from about 0.001 to about 8% by weight (preferably from about0.02 to about 8% by weight). When carriers used for encapsulation areincluded, the usage level of the encapsulated sweetener will beproportionately higher. Combinations of sugar and/or non-sugarsweeteners can be used in the chewing gum formulation processed inaccordance with the invention. Additionally, the softener may alsoprovide additional sweetness such as with aqueous sugar or alditolsolutions.

[0207] If a low calorie gum is desired, a low caloric bulking agent canbe used. Examples of low caloric bulking agents include polydextrose,Raftilose, Raftilin, fructooligosaccharides (NutraFlora®), palatinoseoligosaccharides; guar gum hydrolysates (e.g. Sun Fiber®) orindigestible dextrins (e.g. Fibersol®). However, other lowcalorie-bulking agents can be used.

[0208] Further chewing gum additives, which may be included in thechewing gum mixture processed in the present process, includesurfactants and/or solubilisers, especially when pharmaceutically orbiologically active ingredients are present. As examples of types ofsurfactants to be used as solubilisers in a chewing gum compositionaccording to the invention reference is made to H. P. Fiedler, Lexikonder Hilfstoffe für Pharmacie, Kosmetik und Angrenzende Gebiete, page63-64 (1981) and the lists of approved food emulsifiers of theindividual countries. Anionic, cationic, amphoteric or non-ionicsolubilisers can be used. Suitable solubilisers include lecithin,polyoxyethylene stearate, polyoxyethylene sorbitan fatty acid esters,fatty acid salts, mono and diacetyl tartaric acid esters of mono anddiglycerides of edible fatty acids, citric acid esters of mono anddiglycerides of edible fatty acids, saccharose esters of fatty acids,polyglycerol esters of fatty acids, polyglycerol esters ofinteresterified castor oil acid (E476), sodium stearoyllatylate, sodiumlauryl sulfate and sorbitan esters of fatty acids and polyoxyethylatedhydrogenated castor oil (e.g. the product sold under the trade nameCREMOPHOR), block copolymers of ethylene oxide and propylene oxide (e.g.products sold under trade names PLURONIC and POLOXAMER), polyoxyethylenefatty alcohol ethers, polyoxyethylene sorbitan fatty acid esters,sorbitan esters of fatty acids and polyoxyethylene steraric acid esters.

[0209] Particularly suitable solubilisers are polyoxyethylene stearates,such as for instance polyoxyethylene(8)stearate andpolyoxyethylene(40)stearate, the polyoxyethylene sorbitan fatty acidesters sold under the trade name TWEEN, for instance TWEEN 20(monolaurate), TWEEN 80 (monooleate), TWEEN 40 (monopalmitate), TWEEN 60(monostearate) or TWEEN 65 (tristearate), mono and diacetyl tartaricacid esters of mono and diglycerides of edible fatty acids, citric acidesters of mono and diglycerides of edible fatty acids, sodiumstearoyllatylate, sodium laurylsulfate, polyoxyethylated hydrogenatedcastor oil, block copolymers of ethylene oxide and propyleneoxide andpolyoxyethylene fatty alcohol ether. The solubiliser may either be asingle compound or a combination of several compounds. In the presenceof an active ingredient the chewing gum may preferably also comprise acarrier known in the art.

[0210] The chewing gum centers provided herein may contain aroma agentsand flavoring agents including natural and synthetic flavorings e.g. inthe form of natural vegetable components, essential oils, essences,extracts, powders, including acids and other substances capable ofaffecting the taste profile. Examples of liquid and powdered flavoringsinclude coconut, coffee, chocolate, vanilla, grape fruit, orange, lime,menthol, liquorice, caramel aroma, honey aroma, peanut, walnut, cashew,hazelnut, almonds, pineapple, strawberry, raspberry, tropical fruits,cherries, cinnamon, peppermint, wintergreen, spearmint, eucalyptus,mint, fruit essence such as from apple, pear, peach, strawberry,apricot, raspberry, cherry, pineapple, and plum essence. The essentialoils include peppermint, spearmint, menthol, eucalyptus, clove oil, bayoil, anise, thyme, cedar leaf oil, nutmeg, and oils of the fruits (e.g.lemon, bergamot and orange) as mentioned above.

[0211] The chewing gum flavor may be a natural flavoring agent, which isfreeze-dried, preferably in the form of a powder, slices or pieces ofcombinations thereof. The particle size may be less than 3 mm, such asless than 2 mm, more preferred less than 1 mm, calculated as the longestdimension of the particle. The natural flavoring agent may be in a formwhere the particle size is from about 3 μm to 2 mm, such as from 4 μm to1 mm. Preferred natural flavoring agents include seeds from a fruit e.g.from strawberry, blackberry and raspberry.

[0212] Various synthetic flavors, such as mixed fruit flavors may alsobe used in the present chewing gum centers. As indicated above, thearoma agent may be used in quantities smaller than those conventionallyused. The aroma agents and/or flavors may be used in an amount of from0.01 to about 30% by weight (preferably from 0.01 to about 15% byweight) of the final product depending on the desired intensity of thearoma and/or flavor used. Preferably, the content of aroma/flavor is inthe range of 0.2 to 3% by weight of the total composition.

[0213] Also various acids are used typically in combination with fruitflavors, such as adipinic acid, succinic acid, fumaric acid, or saltsthereof or salts of citric acid, tartaric acid, malic acid, acetic acid,lactic acid, phosphoric acid and glutaric acid.

[0214] In one embodiment, the chewing gum center composition comprises apharmaceutical or biological active substance. Examples of such activesubstances, a comprehensive list of which is found e.g. in WO 00/25598and which is incorporated herein by reference, include drugs, dietarysupplements, antiseptic agents, pH adjusting agents, anti-smoking agentsand substances for the care or treatment of the oral cavity and theteeth such as hydrogen peroxide and compounds capable of releasing ureaduring chewing. Examples of active substances in the form of agentsadjusting the pH in the oral cavity include: acids, such as adipinicacid, succinic acid, fumaric acid, or salts thereof or salts of citricacid, tartaric acid, malic acid, acetic acid, lactic acid, phosphoricacid and glutaric acid and acceptable bases, such as carbonates,hydrogen carbonates, phosphates, sulphates or oxides of sodium,potassium, ammonium, magnesium or calcium, especially magnesium andcalcium.

[0215] The gum center of coated chewing gum elements according to theinvention can have any form, shape or dimension that permits the chewinggum center to be coated by use of any conventional coating processincluding those described in the following. Accordingly, the gum centermay e.g. be in a form selected from a pellet, a cushion-shaped pellet, astick, a tablet, a chunk, a pastille, a pill, a ball and a sphere.

1. Chewing gum comprising gum base, sweetener and flavor, wherein at least a part of said gum base comprises at least one biodegradable polymer, tan(delta) is at least 0.6 within the linear viscoelastic region (LVR) of the chewing gum and the tan(delta) is defined as (loss modulus G″/storage modulus G′)
 2. Chewing gum according to claim 1, wherein the tan(delta) increases outside the linear viscoelastic region (LVR).
 3. Chewing gum according to claim 1 or 2, wherein the tan(delta) is tuned by means of at least one plasticizer.
 4. Chewing gum according to any of claims 1 to 3, wherein the tan(delta) is increased by adding plasticizer to the chewing gum.
 5. Chewing gum according to any of claims 1 to 4, wherein the tan(delta) is increased outside the linear viscoelastic region (LVR) by adding plasticizer to the chewing gum.
 6. Chewing gum according to any of claims 1 to 5, wherein the slope of the tan(delta) outside the linear viscoelastic region (non-LVR) relative to oscillation torque is increased by adding further plasticizer to the chewing gum.
 7. Chewing gum according to any of claims 1 to 6, wherein the tan(delta) increases to at least 1.0 in the nonlinear viscoelastic region (non-LVR)
 8. Chewing gum according to any of claims 1 to 7, wherein the tan(delta) increases to at least 1.0 in the nonlinear viscoelastic region (non-LVR) when an oscillation torque of 10000 microN·m has been reached.
 9. Chewing gum according to any of claims 1 to 8, wherein the tan(delta) increases to at least 1.3 in the nonlinear viscoelastic region (non-LVR) when an oscillation torque of 10000 microN·m has been reached and when measured on chewed chewing gum.
 10. Chewing gum according to any of claims 1 to 9, wherein the tan(delta) increases to at least 1.3 in the nonlinear viscoelastic region (non-LVR) when an oscillation torque of 11000 microN·m has been reached and when measured on chewed chewing gum.
 11. Chewing gum according to any of claims 1 to 10, wherein the tan(delta) increases to at least 1 within one decade from the transition between the linear viscoelastic region into the nonlinear viscoelastic region, when the tan(delta) measured as a function of oscillation torque.
 12. Chewing gum according to any of claims 1 to 11, wherein the tan(delta) is tuned to have a maximum of approximately 2.0 or preferably 1.7 when the oscillation torque is less than 13000 microN·m.
 13. Chewing gum according to any of claims 1 to 12, wherein the tan(delta) is measured on pre-chewed chewing gum.
 14. Chewing gum according to any of claims 1 to 13, wherein the tan(delta) is measured at mouth temperature.
 15. Chewing gum according to any of claims 1 to 14, wherein the tan(delta) is measured at 37 C°.
 16. Chewing gum according to any of claims 1 to 15, wherein the tan(delta) is measured within a range of approximately 30 C° to 45 C°.
 17. Chewing gum according to any of claims 1 to 16, wherein the tan(delta) is measured at an oscillation frequency corresponding to typical chewing frequency.
 18. Chewing gum according to any of claims 1 to 17, wherein the tan(delta) is measured at an oscillation frequency of 1.0 Hz.
 19. Chewing gum according to any of claims 1 to 18, wherein the tan(delta) is measured at an oscillation frequency within a range of 0.5 to 2 Hz.
 20. Chewing gum according to any of claims 1 to 19, wherein said plasticizers comprise emulsifiers.
 21. Chewing gum according to any of claims 1 to 20, wherein the chewing gum comprises an amount of emulsifiers of 0 to 5% w/w.
 22. Chewing gum according to any of claims 1 to 21, wherein said plasticizers comprises fat
 23. Chewing gum according to any of claims 1 to 22, wherein the chewing gum comprises an amount of fat of 0 to 15% w/w.
 24. Chewing gum according to any of claims 1 to 23, wherein said plasticizers comprises wax.
 25. Chewing gum according to any of claims 1 to 24, wherein the chewing gum comprises an amount of wax of 0 to 15% w/w.
 26. Chewing gum according to any of claims 1 to 25, wherein said plasticizers comprise flavor, preferably liquid flavor.
 27. Chewing gum according to any of claims 1 to 26, wherein the chewing gum comprises an amount of flavor of 0 to 30% w/w.
 28. Chewing gum according to any of claims 1 to 27, wherein said plasticizers comprise liquid sweeteners.
 29. Chewing gum according to any of claims 1 to 28, wherein the chewing gum comprises an amount of liquid sweeteners of 0 to 30% w/w.
 30. Chewing gum according to any of claims 1 to 29, wherein the amount of plasticizers in the chewing gum is at least 1% w/w.
 31. Chewing gum according to any of claims 1 to 30, wherein the amount of plasticizers in the chewing gum is at least 5% w/w.
 32. Chewing gum according to any of claims 1 to 31, wherein the amount of plasticizers in the chewing gum is at least 10% w/w.
 33. Chewing gum according to any of claims 1 to 32, wherein the amount of plasticizers in the chewing gum is at least 15% w/w.
 34. Chewing gum according to any of claims 1 to 33, wherein the amount of plasticizers in the chewing gum is at least 20% w/w.
 35. Chewing gum according to any of claims 1 to 34, wherein the amount of plasticizers in the chewing gum is at least 30% w/w.
 36. Chewing gum according to any of claims 1 to 35, wherein the chewing gum comprises an amount of biodegradable polymers of 1 to 99% w/w.
 37. Chewing gum according to any of claims 1 to 36, wherein the chewing gum partly comprises non-biodegradable polymers.
 38. Chewing gum according to any of claims 1 to 37, wherein the chewing gum polymers consist of biodegradable polymers.
 39. Chewing gum according to any of claims 1 to 38, wherein the linear viscoelastic region (LVR) has a maximum oscillation torque within a range of 300 microN·m to 10000 microN·m.
 40. Chewing gum according to any of claims 1 to 39, wherein the linear viscoelastic region (LVR) has a maximum within a range of 400 microN·m to 3000 microN·m.
 41. Chewing gum according to any of claims 1 to 40, wherein the linear viscoelastic region (LVR) has a maximum within a range of 500 microN·m to 2000 microN·m.
 42. Chewing gum according to any of claims 1 to 41, wherein the tan(delta) critically is greater than 0.7, preferably greater than 0.8, preferably greater than 1.0 where the tan(delta)(crit) is the tan(delta) value corresponding to delta(crit) in a tan(delta) vs. oscillation torque measurement and where delta (crit) represents the critical oscillation torque determined in a G′ vs. oscillation torque measurement, which describes the oscillation torque at the point where the material begins to deform, i.e. the point where the oscillation torque invokes a transition from the LVR to the non-LVR.
 43. Chewing gum according to any of claims 1 to 42, wherein the tan(delta) critically is less than 1.0, preferably greater than 0.9, preferably greater than 0.8.
 44. Chewing gum according to any of claims 1 to 43, wherein the poly(ester-carbonate) comprises monomers selected from the group consisting of lactide, glycolide, ε-caprolactone, δ-valerolactone, β-propiolactone, dioxanone (ester-ether), tri-methylene carbonate, ethylene carbonate, propylene carbonate, 5,5 di-methyl-1,3-dioxane-2-one and 5-methyl-1,3-dioxane-2-one.
 45. Chewing gum according to any of claims 1 to 44, wherein the polyester is a homopolymer.
 46. Chewing gum according to any of claims 1 to 45, wherein the polyester is a co-polymer.
 47. Chewing gum according to any of claims 1 to 46, wherein the polyester is a ter-polymer.
 48. Chewing gum according to any of claims 1 to 47, wherein the molecular weight of the degradable polymer is in the range of 500-10.000 g/mol.
 49. Chewing gum according to any of claims 1 to 48, wherein the molecular weight of the degradable polymer is in the range of 10000-100.000 g/mol.
 50. Chewing gum according to any of claims 1 to 49, wherein the molecular weight of the degradable polymer is in the range of 100000-1000.000 g/mol.
 51. Method of manufacturing a biodegradable chewing gum comprising the steps of providing at least one biodegradable polymer and adding plasticizer to the said at least one biodegradable polymer in an amount suitable for tuning the balance between the storage modulus and the loss modulus.
 52. Method according to claim 51, whereby said chewing gum comprises the chewing gum according to any of the claims 1 to
 50. 53. Chewing gum according to any of claims 1 to 50, wherein said plasticizers comprise solubilizers.
 54. Chewing gum according to claim 51, wherein the chewing gum comprises an amount of solubilizers of 0 to 5% w/w. 